An active-RC reconfigurable lowpass-polyphase Tow-Thomas biquad filter

A novel active-RC biquad is presented which can be reconfigured as a polyphase filter for a low IF wireless receiver architecture, and as a lowpass filter for a zero IF wireless receiver architecture. A second order lowpass-polyphase reconfigurable filter is implemented to illustrate the technique. A 1.8 V fully differential operational amplifier in 0.18 /spl mu/ CMOS technology is used as the active element.